REDUCTION OF STRESS-INDUCED ANALGESIA FOLLOWING ETHANOL EXPOSURE IN MICE

In the present study, we examined the effects of ethanol treatment on the subsequent expression of opioid and nonopioid forms of swim stress -induced analgesia (SSIA). In Experiment 1, mice were injected with et hanol (2.5 g/kg, IF) or an equal volume of saline once a day for two d ays. Animals received no treatment on day 3. On day 4, the animals wer e tested for opioid (3-min swim in water maintained at 32 degrees C) o r nonopioid (3-min swim in water maintained at 20 degrees C) SSIA in t he hotplate test (52 degrees C). Mice pretreated with ethanol injectio ns showed a decrease in nonopioid SSIA, but not in opioid SSIA. In Exp eriment 2, mice were given an ethanol solution (10%) or tap water to d rink for 15 days. On day 16, all animals were given tap water to drink . On day 17, the animals were tested for opioid or nonopioid SSIA. Nei ther form of SSIA was modified in mice that drank the ethanol solution . These results show that ethanol pretreatment can modify nonopioid en dogenous analgesic responses in mice. Further, the route of administra tion influences the effects of ethanol pretreatment on SSIA.